Liquid sterilizer



April 23, 1935. I G. F. LINE LIQUID STEILIZER 2 Sheets-Sheet 1 Filed June 4, 1934 VT /M April 23, 1935o G. F. LINDE I LIQUID STERILIZER 2 Sheets-Sheet 2 Filed June` 4, 1934 Patented Apr. 23, 1935 'LIQUID STERILIZER.

Gustave Linde, Madison, Wis., assignor to Scanlan-Morris Company, Madison, Wis., a

corporation of Wisconsin n Y Application .lune 4, i934, Serial No. 728,847

8 Claims.

This invention relates to the art of liquid sterilizing apparatus. Apparatus of this character, extensively used in hospitals and bacteriological laboratories, commonly comprises a tank to receive the liquid to be sterilized by heat, means for heating the liquid to a sterilizing temperature, and. a glass gauge mounted on one side of the tank to indicate to the operator the level oi t e liquid in the tank. The gauge glass, being a relatively long narrow tube entirely surrounded by the air in the room, cools rapidly and consequently neither the glass itself nor Ythe body oi liquid therein reaches a sterilizing temperature during the treatment ot .the main body or" liquid in the tank, so that the liquid in the gauge, being always in communication with the liquid in the tank,V more cr less contaminates the sterilized water in the tank. One object of the present invention is to provide in association with the tank and gauge an elicient means for thoroughly sterilizing the gauge and the water therein so that the tank and the main body ci water therein will not become contaminated from the water in the gauge.

Again, in order to draw on the sterilized liquid from the tank it is necessary, of course, to vent the tank to air which -fills the tank as the liquid is drawn 01T, and unless the incoming air is perfectly pure and clean, bacteria may be introduced into the tank with the air. Oi course, pure air carries no bacteria, but most air is more or less dust laden, and the bacteria are found in the dust. Another object of the invention is, therefore, to provide an attachment for sterilizers of this type by which the incoming air can be thoroughly washed and freed ci allbacteria. 1 One means by which the above stated objects may be attained in accordance with the principle of the present invention is illustrated in the kaccompanying drawings, in which:

Fig. 1 is a vertical sectional View of the complete apparatus, with certain of the pipes appearing in elevation.

Fig. 2 is an enlarged sectional detail of the air washer and sterilizer, showing its condition when steam from the sterilizing tank is discharging therethrough. Y

Fig. 3 is a similar view of the air washer and sterilizer showing its condition when steam is being condensed in the sterilizing tank, or the sterilized waterY is being drawn therefrom, or both, and air is being admitted through the washer and sterilizer to the sterilizing tank under the vacuum pull in the latter.

Fig. 4 is a plan section of a sanitary air gap litt-ing at the lower end of the system through f which the incoming air is admitted to the air washer and sterilizer.A y

Fig. 5 is a sectional detail on the line 5 5 of Fig. l.'

Fig. 5 is a View similar to Fig. l illustrating a recessedin-wall installation. j

Referring to the drawings, IIJ designates a tank adapted to,contain a body of water or other liquid to be sterilized, the liquid being heated by any suitable means such, for instance, as a steam coil il. From the center of the concave bottom wall it oi the tank It a valve-controlled drain pipe l2 leads 'into a waste tting I3, the lower end of which communicates by a short pipe section til and elbow I5vwith a drain pipe I6 leading to the sewer. The purpose of the last described parts, is, of course, to drain off, from time to time, any sediment that may accumulate in the bottom of the tank Ill. 20

' in one side `of the `tank l@ are mounted upper and lower standard 4gauge glass fittings I1 and I8 equipped with manually operated Valves I9 and' 2e, respectively, which are normally open and closed only in an emergency such as the breaking of the `gauge glass, and between these flttingsismounted the gauge glass 2|. Within the gauge glassZI and coaxial therewithis the upper section of a steam pipe 22, the lower end of which upper section maybe mounted in the axially bored lower plug 23 of the fitting I8, the lower portion of the upper section 'of pipe 22 being bent laterally to clear the needle valve 20, as shown in Fig. 5. The upper end of the upper section of steam pipe l.t2 communicates freely with the chamber of the upper gauge tting I1 so that it is in free communication with the interior of the upper portion of the tank iii. The upper end of the lower section of pipe 22 is mounted in the plug 23 and its lower end connects into a thermostatic steam trap 2li ofthe well known Vtype wherein a bellows diaphragm 25, that is eX- pansible by the heat of the steam, carries a Valve 2t cooperating with a valve seat 2 inthe bottom 4- of the trap so that, shortly after the steam enters the trap thervalve 26 is closed on its seat by the Y diaphragm-25 so as to prevent'further escape of steam.

Connected into the lower end of the steam trap 2f?, is an air washer andsterilizer, the structural details'of which are best illustrated in Figs. 2 andV 3, .and comprise an outer steam and air tight casing 28 closed at its upper and lower ends Y by heads 29 and 30, an inner tube 3l secured at k55 its open upper end in the head 29, and an outer tube 32 encircling the inner tube 3l, open at its upper end, and at its lower end closed by a cap 33 in which the lower end of the inner tube 3l is seated and sealed. The upper head 29 of the washer and sterilizer is equipped with a threaded nipple 34 that screws into the lower end of the steam trap 24, and in the lower portion of the inner tube 2l is a ring of holes 35 that may be covered with screens 36 Where, as is preferable, the inner tube 3l is supplied with a body 0f glass or porcelain beads 31, which are used to break up bubbles in the air that is passing through the body of water in the tube 3l.

The lower head 3i) of the air washer and sterilizer is formed with a tapped nipple 38 to receive a pipe 39 that communicates with the drain pipe i 2 through a T-tting il in the latter.

The sanitary air gap drain iitting i3, which is preferably employed, is a hollow inverted pearshaped structure tapped to receive the threaded lower end of the drain pipe l2, and formed in one side thereof with a substantially semi-circular air inlet opening l l which straddles an internal baiile d2 mounted in the upper end of the fitting, the barile 42 having a biased open side remote from the air gap or inlet 4l, so that sediment deposited from the pipe l2 cannot splash on and thus foul or obstruct the air gap or mouth 4I.

Briefly describing a cycle of operation, the tank lil is filled in the conventional manner and steam turned on to sterilize the water. The air above the water is expanded by the heat and escapes through tube 22 in the gauge glass, through the thermostatic trap 24 and through the washer and sterilizerZS to the sanitary air gap fitting i3 which is open to the air through the opening di. This air in its escape depresses the liquid level in the inner tube 3| down to the holes 35, causing a partial overiiow of the water in the washer and sterilizer, as shown in Fig. 2. During the sterilizing period the thermostatic trap is intermittently draining condensate into the inner tube 3l, thereby replenishing the condensate blown cii by the air. The reason for this intermittent action of the steam trap during the sterilizing period is found in the fact that, after the trap valve has closed by reason of the heat imparted to the motor diaphragm, a leg of steam is trapped in the pipe 22 above the trap.

As this leg of steam cools by radiating its heat,

condensate is formed, and this condensate is drained to steam trap 24 by pipe 22, whichcools motor diaphragm causing it to contract thereby raising the trap valve 26 from seat 21 only sufliciently to4 allow condensate to drain from trap into the air washer and sterilizer. The steam in pipe 22 which follows the condensate again expands the motor diaphragm and seats trap valve 2S against the seat 2l, until this leg of steam has cooled sufliciently to form condensate, at which time the motor diaphragm will again contract and raise trap valve 26 from seat 2l only sufliciently to drain the condensate into the washer and sterilizer. Each time the trap valve 26 seats against the seat 21, steam condensate forms and collects in the chamber of the trap above the valve, and each time the valve rises from the seat, this condensate drains into the air washer and sterilizer. At the end of the sterilizing period, r'when the steam is turned oli, and the water in the tank begins to cool, stopping the iiow of steam through the pipe 22, the natural radiation of the thermostatic trap will cool the. expanding element in the trap, causing the trap valve to rise from its seat approximately one-eighth to one-fourth of an inch, allowing air to ilow into the sterilizer tank as the steam condenses or Water is drawn therefrom. When air flows through the washer and sterilizer due to reduced pressure in the sterilizing tank, the atmospheric pressure will cause the liquid level to be lowered between the inner and outer tubes and to the level of the holes 35 in the inner tube. This, of course, raises the liquid level in the inner tube, as is shown in Fig. 3. After the level between the inner and outer tubes has been lowered to the holes 35, air enters through the holes and bubbles up through the liquid column washing and sterilizing the air. The liquid in the inner tube 3i forms an eifective seal against unsterlized air entering the sterilizer tank, since the air can enter the tank only through the body of water in the tube 3l. When steam is formed in the sterilizer, a considerable quantity thereof fiows through the system before the diaphragm in the thermostatic trap expands sufficiently to close the trap; and this steam iiowing through the washer and sterilizer sterilizes it effectively.

Fig. 6 illustrates an application of the invention to a sterilizer installation of the concealed type; that is, an installation wherein the sterilizer tanl; and its adjuncts, with the exception of the gauge and control valves, are recessed a wall of an operating room, clinic chamber, or

other compartment, so as to be substantially concealed. In such installation P designates a wall or panel, behind which the sterilizer. tank I is located. The gauge glass ttings l l and I3 are mounted on the outer side or" the wall P and are connected to the tank by upper and lower pipes and 5l. The lower gaugeglass iitting I8 is slightly modilied as shown to provide around the valve chamber an annular passage 52 that receives the lower end of the pipe 22 and communicates with a pipe 53 surrounding the pipe 5|; the inner end or" the pipes 53 and 5l being connected into a fitting 54 that is secured to the wall of the tank lil by a threaded nipple 54 and nut 55. From the annular steam space between the pipes 5I and 53 a pipe 56 extends downwardly and connects into the steam trap 24, the pipes 53 and 5B being virtually an extension of the pipe 22.

In this form of installation the steam supply and exhaust valves 57 and 58 to and from the heater coil l l are operated from the front of the wall P by long valve stems V59 and Ell respectively, and the drain valve 6l is operated by a similar long valve stem 6.2. In this View I have also indicated the water supply and draw off devices to the tank it, the water supply pipe appearing at 63 connecting with the lower end of an ordinary water filter 64, the upper end of which communicates by pipe 55 with the interior of the tank l0. The water is turned onrand oii by a valve 66 likewise equipped with a stem 61 extending through the wall P. 68 designates the water draw-off pipe communicating with the lower portion of the tank I9 and extending through the wall P and equipped on its outer end. with a valve-controlled faucet 69.

From the foregoing it will be seen that the invention accomplishes the two desirable results of, first, thoroughly sterilizing the gauge glass and liquid and preventing any contamination of the sterilized liquid from the latter; and, secondly, washing and sterilizing the air that is drawn into the tank as the sterilized liquid is withdrawn or the steam in the tank is condensed;

1. In an apparatus for sterilizing liquids, thev combination with a tank, and a Water level gauge communicating with the top and lbottom portions of said tank, of'an imperforate steam pipe extending through the water chamber of said gauge and communicating with the steam space of said tank.

2. In an apparatus for sterilizing liquids, thev combination with a tank, upper and lower valve ttings on said tank, and a gauge glass mounted in and between said fittings, of a steam pipe having its upper end in communication with said upper valve iitting and extending through said gauge glass and lower tting.

3. In an apparatus for `sterilizing liquids, the combination with a tank, and a water level gauge communicating with the top and bottom portions of said tank, of a steam pipe extending through the water chamber of saidgauge and communicating with the steam space of said tank, and a thermostatic steam trap on said steam pipe beyond said gauge.

4. In an'apparatus for sterilizing liquids, the combination with a tank, upper and lower Valve fittings on said tank, and a gauge glass mounted in and between said fittings, of a steam pipe havingV its upper end in communication with said upper Valve fitting and extending through said gauge glass and lower fitting, and a thermostatic steam trap on said steam pipe beyond said lower fitting.

5. In an apparatus for sterilizing liquids, the combination with a tank, and a water level gauge communicating with the top and bottom portions of said tank, of an imperforate steam outlet and air inlet pipe extending through the water chamber of said gauge and communicating with the steam space of said tank.

6. In an apparatus for sterilizing liquids, the combination with a tank, and a water level gauge communicating with the top and bottom portions of said tank, of a steam outlet and air inlet pipe extending through the water chamber of said gauge and communicating with the steam space of said tank, and an air washer and sterilizer communicating with the steam discharge end of said pipe.

'7. In an apparatus for sterilizing liquids, the combination with a tank, and a water level gauge communicating with the top and bottom portions of said tank, of a steam outlet and air inlet pipe extending through the water chamber of said guage and communicating with the steam space of said tank, a thermostatic steam trap on said pipe beyond said gauge, vand an air washer. and sterilizer communicating with the discharge end of said steam trap.

8. In an apparatus for sterilizing liquids, the combination with a tank, and a water level gauge communicating with the top and bottom portions of said tank, of a steam outlet and air inlet pipe extending through the water chamber of said gauge and communicating with the steam space of said tank, a thermostatic steam trap on said pipel beyond said gauge, an air washer and sterilizer communicating with the discharge end of said steam trap, and a drain tting communicating with the discharge end of said washer and sterilizer, said tting having an air inlet opening.

GUSTAVE F. LINDE. 

